'86 K100RT

[Pisano9]

Tell me what you can about this bike, please. What tires work best for touring? Will it take radials? What oil is best? Is synthetic oil a good thing in this bike? What about ethanol laced fuels (10 percent), will it bother the fuel injection? Is a K&N air filter a worthy investment for this year bike?

 

I have many more questions but hold off? Thanks for looking

[Paul Mihalka]

Tires that I know are available and will work: Front 100/90x18 Metzeler Lasertec. Rear 130/90x17 Metzeler ME88. The bike was not designed for radials.

Oil: My '86 K75 kept in perfect condition with Castrol GTX 20/50 for over 200K miles. BMW oils were not invented yet .

Air filter: I used the K&N simply because it is good for 50K miles without service and changing the air filter on that K bike is a P in the A.

[Pisano9]

Thanks Paul good info. You said if asked, I would get answers. Thanks. The bike has Dunlop 491's on it now, which is what I run on my wing, but I have always liked Metzlers better from the ol'dirt days

[RFW]

Tell me what you can about this bike, please. What tires work best for touring? Will it take radials? What oil is best? Is synthetic oil a good thing in this bike? What about ethanol laced fuels (10 percent), will it bother the fuel injection? Is a K&N air filter a worthy investment for this year bike?

 

I have many more questions but hold off? Thanks for looking

I have one and ride it all year to work and on longer (1600 km or more) trips.

 

Tires: Bias, NOT radials. Michelin Macadam 50s work well as do Metzeler 880s (front and rear), and also Metzeler 880 (rear) and Lasertecs (front).

 

Ethanol gas: NO! BMW warns against this. Tere is no benefit to it, and the rubber seasl were not designed for it.

 

K+N filter? A total waste of money. Worse, even. It will not add any power, and its filtration is worse than the stock one. The stock filter is huge and effective.

 

Oil: BMW has specifically warned in an earlier service bulletin that especially applies to older bikes like this, that standard car oils that meet any standard past SH are NOT to be used because later oils have reduced ZDDP (extreme pressure) additive. Motorcycle-specific oils on the other hand are a ripoff. I use Shell's Rotella-T or Chevron's Delo400, 15W40. Both are so-called "Diesel Oils", and meet BMW's requirement of a "Heavy Duty Brand Name" oil. They cost half of what a motorcycle oil like Spectro costs and are at least as good (probably better).

 

If you doubt the wisdom in this, note that my bike has nearly 200,000 on the original engine, and it burns ZERO oil. I change oil every 6 months or less, and in spite of using it every day, the oil level remains unchanged between oil changes.

 

I know this bike inside and out, so PM me if you need to know more about stuff like spline lube and other requirements. These things are bulletproof if treated with even a little respect.